Many kinds of input devices are used with electronic devices such as computers. A mouse is probably the most common input pointing device used with a computer, but touchpads are also frequently used; almost all laptop computers are presently equipped with a touchpad. A touchpad detects the position where a user's finger touches the touchpad and uses the detected position to control a cursor on the computer screen and select commands for the computer.
Two types of electrical touchpad—resistive or capacitive—are the most common, but optical fingerprint sensors have recently become available, normally for use as a security key. For example, fingerprint sensors can be used to unlock a computer such that the computer could be operated, and even used to unlock a physical door to enter a building or room.
Optical gesture recognizers have also recently become available. A gesture recognizer uses a camera to detect an object, for example a hand. The detected image of the hand is then analyzed by a computer or processor to recognize the gesture made by the hand. The detected gesture can be used to select commands for the computer, for example in a computer and/or video game.